Jerry BussTold VERY Young GFKEEP QUIET!!!

3/29/2013 12:40 AM PDT

Jerry Buss Told Young Girlfriend ... KEEP QUIET!!!!

EXCLUSIVE

The woman who scored an expensive condo, Bentley AND MORE from deceased L.A. Lakers owner Jerry Buss had clear instructions from the mogul -- KEEP QUIET about the relationship.

Delia Cortez tells TMZ ... she started dating Jerry "years ago" when she lived in Marina del Rey, CA ... a beachside community in L.A.. When the relationship got hot and heavy, she says Jerry moved her to Honolulu, Hawaii to keep things on the down low, and bought her a condo and a 2009 convertible Bentley.

Delia, who's in her late 20s, says she knew all along ... Jerry, who died at 80, had multiple, young girlfriends. Jerry was famously a player in L.A., but Delia says she was his #1. Delia ungenerously added, "The others were just slutty arm candy."

Delia tells TMZ ... in addition to giving her the condo and the Bentley in his will, Jerry also left her a large amount of money, though she would not disclose the amount and how she got it -- through the will or otherwise.